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Corliss Gear.


If the propeller sinks below the normal, water rises in D, and,
compressing the air in F, presses on diaphragm H, lifting K L and
moving K z round fulcrum z. Valve M being opened to steam at
the bottom end, piston P is raised, thus depressing the rod s x and
opening wider the engine throttle valve. But, as s moves down,
the lever K z is turned round K as a fulcrum, and valve M is once
more placed in mid position. Suppose the propeller rises, the air
in F becomes more rare, and spring j moves L K downward,
opening M at the top, bringing QR down, and raising ST, thus,
partly closing the throttle valve. (See p. 1-144.)

Corliss Valve Gear.—Of all the ' trip' gears,* this is
probably best known. In Fig. 650 the upper diagram shews the
valve gear, the lower being a section, through the cylinder and
valve chambers. There are several advantages possessed by this
valve arrangement and gear, some being common to other trip
gears : (i) a sharp cut-off is obtained, when the 'trip ' takes place,
preventing wire-drawing; (2) an easier-working form of valve, g,
is adopted; (3) steam and exhaust parts being separate, there is
less loss by initial condensation; (4) clearance is very small ;
(5) the variable cut-off" is automatic.

The valves a& admit steam, and ee pass the exhaust, being
represented in plan at g. They are hollow cylinders having a

* Term given to rapid cut-off gears, worked by the trip of a valve lever.